BDE cam gears - caution

The car that we fitted these to was using a MAP sensor and we had a Lamda sensor on each exh bank, we could see by the exh readings that one side was not doing what the other was doing.

 

Sorry it has taken this long to get any sort of feedback to everyone on this issue - I finally received the sprockets from Z1 a week ago.

As Glenn mentioned, due to the distances involved we decided it was cost effective for him to disassemble the offending sprocket to see if he could see something obvious that was causing the problem. I want to be clear for anyone that thinks they may have an issue with one of my rebuilds: as stated in the literature included with all my VTCs, I do not encourage anyone to disassemble them unless I have been consulted first. On to the analysis...

I first disassembled the sprocket Glenn had and noticed right away the piston was jammed into its bore. When I finally got it out, there were massive linear scratches formed on the ID of the sprocket body bore, on the ID/OD of the piston and the OD of the cam helix (all of these parts are identified in the first picture below). The scratches were extreme enough on the piston OD to smear its metal into the compression ring groove thereby locking the ring in its groove. These scratches are inline with the motion of the piston working within the sprocket and indicative of foreign debris in the oil. I am not surprised the VTC would not return to its static zero position with Glenn's test rig.

Next, I disassembled the sprocket that was untouched by Glenn. Similar scratches but to a lesser degree were noted. Most importantly, this sprocket still had residual oil left in it. The first thing I noticed was a rather large chunk of copper/bronze looking material (see second picture below) and excessive metallic glitter in the oil. I should add, there are no parts within the VTCs that are made of copper or bronze.

In my opinion, the engine these sprockets were installed onto is not in good health. Something made of copper/bronze is coming apart within it (bearings, wrist pin bushings, aftermarket valve guides?), contaminating the oil with its debris, affecting the proper operation of the VTCs and who knows what else. Possibly, this is why the cam bearing clearances were out of spec in the first place. This is an instance of the symptom not being the cause of the problem.

I can assure everyone that I do not ship VTCs with debris inside them or damaged surfaces as shown below. I have absolutely no control over the condition of the engines in which my VTCs are installed onto but I am willing to address any and all concerns customers might have.

Unrelated to this issue, but there was mention in this thread of some noise occuring with some engines still - this is typically with JWT 500 cams and I am working with multiple users to test a fixes. Most notably is the use of a restrictor in the VTC bolts to restrict the oil pressure the VTC is exposed to when it is off. I will add that for every JWT 500 engine that makes some noise, there are many others that do not; the reason behind this is unclear.

Again, I must stress, I have no control over an engine's specs such as:

1. are the VTC oil restrictors in place in the engine block's deck surface?
2. what is the installed valve spring pressure?
3. what viscosity oil is used?
4. what is the ambient temperature when/if noise occurs?
5. is there foreign debris in the oil?
6. if an adjustable sprocket, are the adjuster bolts torqued to spec?

These are all common issues that have been identified as contributors to VTC noise and addressing them typically cures the issue.

Lastly, I want to mention that VTCs, BDE, OE new or old, do not typically make noise immediately when installed fresh onto an engine. You can prove this to yourself by removing the front cover of a currently noisy VTC, draining whatever oil comes out of it, reinstalling the cover and viola, the noise will be gone temporarily. This is due to air trapped within the VTC acting as a compressible cushion and this is why I set a 5000 mile noise-free target for all test vehicles when I was developing my rebuilds.

Parts Identification


VTC #2 (untouched by Glenn) large chunk of copper/bronze debris


VTC #1 (unassembled by Glenn) bore ID


VTC #1 piston ID


VTC #1 cam helix OD scratches

 

Does that mean the particles are small enough to pass the pickup gauze and have bypassed the filter via the relief valve ?

 

Brett as explained to you in the emails the sprocket I had taken apart had a lot of techniques tried on it in an effort to improve its operation.
One of these techniques was the use of lapping compound, this is the reason for the heavy scratching you see in the bore.

This was NOT present when the gear was first disassembled.

One of the first things done on a fresh engine rebuild is to drain the pil after the first half an hours running & change the filter, I take it a step further using experience from my time in the aircraft industry & cut the filter open & inspect it for debris/metal etc.
This is a dead give away that something could be going wrong with the build.

I can assure you there were no signs of any oil contamination at any stage of the process.
It is well known a freshly rebuilt engine can sometimes have debris inside it - no mater how careful you are it is pretty much expected there will be some flushed out after the first start up or two.
As I said above there was no sign of contamination at any stage - I can assure you I would not go to all this trouble if it were simply a case of debris in the oil!!!

As explained to you more than once this engine has actually had a lot of work done on the parts that would make any difference to the operation of your gears:
Fresh block, rebored, line bored, decked, new jets and oil plugs etc, thoroughly cleaned at three stages, pre lubed and oil pump primed before the sump was fitted.
The entire poil system incl remote filter & oil cooler were flushed also - even though there was never an issue with contamination prior to the build.

The heads were only checked for cam shaft clearance as we had an issue with you gears not operating correctly, this was not picked up by the first tuner & the car actually destroyed the LHS turbo charger during the tune.
After this had happened the filter was again checked - no debris in sight! The turbo had suffered an overheated turbine wheel, damaged blades, went out of balance & then fractured the shaft.

At no stage when removing & refitting these gears (several time I might add!) was there any sign of contamination, factory gears were fitted and these worked perfectly - although we are still waiting for the death rattle. I will be fitting a set of my bolts to this car as they are doing a fine job on mine so I see no reason why they wont work on this one.

There is no chance of air being trapped in the cam gears, centrifugal forces cause the oil to settle at the outer edges of the gears and so the air can come and go from the centre & clears very quickly - within only a couple of cycles tops.

So after wasting crap loads of time & money on this we are told "apparently" the gears were contaminated yet we have seen zero sign of any contamination here on the engine itself. There were no debris in the gear that I took apart (& ultimately destroyed while attempting to fix) it is possible the other gear caught a small amount of debris from the first start up however both gears were thoroughly cleaned of oil during testing of operating pressures. I would be surprised if you found oil heavily contaminated with oil in either gear, both were left to drain of oil on the bench for some time prior to shipping as it's a big no no to send flammables via airfreight.

At this stage I'm feeling pretty much tucked, A product has been purchased & fitted & it has failed to operate in a perfectly normal situation, extensive testing has been carried out & it all points at the product. The product was returned & the manufacturer claims it has been contaminated & has shown photos of this.

Are BDE gears not suitable for installation on freshly rebuilt engines due to the risk that an engine being run in could contaminate the gears and prevent them from working correctly?

I have seen PLENTY of stock engines with seriously contaminated oil due to massive bearing failures, the stock gears operate perfectly if flushed out as per normal procedure.

 

I'm not going to get into a debate over theories of VTC mechanics, you have your ideas and I have mine.

I had a feeling you wouldn't believe me but my observations are honest and without prejudice. All I can tell you is I took the sprockets apart which Z1 sent to me and labeled as coming from you, and the residual oil left in the one you did not disassemble had copper/bronze debris in it. I did not put it in there and the location it was found would make it relatively impossible for it to find its way in there during shipping. Regardless, the rest of the residual oil has a metallic glitter in it and there are other, smaller pieces of similar colored debris also in the picture.

I disagree, large chunks of debris in the oil is not normal. My "claim" is fact, if you choose to not believe what I have found, what would you have me do prove it to you? The moment the sprocket left your hands this became a "you said, he said" situation. I have the integrity to be honest with my findings, if I had found nothing out of the ordinary I would have stated so.

Let's remove this air of distrust and have a third party perform an oil analysis on the suspect engine's oil. I'm sure our mutual customer would be very interested to rule out the possibility of debris circulating through his engine - the chunk that I found could easily clog the oil restrictor to the turbo(s).

Why would this be the case? I rebuild original equipment VTCs; other than the new spring to control the piston better, I do not manufacture replacement parts/pieces nor do I modify the sprockets in any manner that could affect their function as originally designed and certainly not as you have described.

As a side effect of adding the stronger spring my VTC rebuilds require higher oil pressure to fully activate than a stock VTC does. A maximum of 25 psi is the pressure required to fully activate my rebuilds.

Every engine is different and perhaps this one is the exception rather than the rule. I have very close to 500 cars running my rebuilds without the issue you have described - it is inevitable some problems will come up but the shear number of good results far outweighs the bad. I encourage anyone that feels they have a problem with my products to contact me for help and advice.

 

The largest chunk is small enough to pass through the pump pickup screen and yes, it would have to bypass the filter via the relief valves to get into the VTC.

I've never been a big fan of OE oil filter relief valves in performance engines - if the oil filter becomes clogged, then there are larger problems to an engine than the clogged filter.

 

Is the relief valve what feeds the oil cooler on a TT or is that another system again in the filter tree ?

 

The one thing that seems strange to me is that other gears installed on the same engine work fine ? I would have thought that if oil contamination was the cause the other gears tried would soon develop the same noise ? Not taking sides at this stage just saying what i believe would be the result of contaminated oil . Seems rather strange. The particles found may not be the cause of the noise , just because something appears to be a obvious cause it does not mean it is the actual cause. If the debris was removed in your opinion would the noise go away ? Of course they argument could be sorted by sending mungyz a set of gears that had been tested in one of your engines and found to work fine to put into this engine and see if they run problem free. If they play up it would prove you are 100% on the ball , if it works o.k you both learn something ( gears have a fault that requires further investigation ). To me it's no big deal who is at fault here. A he said she said forum does not help anyone and the percieved fight real or otherwise hurts both partys. However proving the cause to the satifaction of mungyz proves to everyone the sellers has the buyers best interest at heart. Hope this gets sorted to both partys satisfaction quickly.
Just my 2 cents worth and not taking sides
Cheers Dave

 

The oil filter by-pass and the oil cooler valve are both located on the TT oil filter tree but they are not the same. The oil filter by-pass is comprised of two small spring loaded balls on the flange where the oil filter screws on.

 

so what pressure is required for the stock gears to fully activate ...?

and is there a way to increase that pressure safely? or its not needed?

 

Brett please understand I'm trying to discuss this in a rational way & the only goal is a satisfied customer (Mike).

The turbo that blew had a good oil supply - as was evident by the oil in the exh after failure, the oil supply to both turbos was checked prior to start up as this car has eaten a turbo in the past. It was actually the same side that went, the turbo was replaced in situ then when the engine came out for other work the turbos were swapped over so the older one was on the side that could be replaced in the car.

I'm not saying you didn't find anything, I'm scratching my head as to why there was never any sign of it prior to them getting to you. It simply makes no sense that there was never any sign of contamination anywhere on anything except now the cam gears.

The car in question is heading back for some other work in the near future, I'd be more than happy to set up a web cam & pull the filter, cut it open as you watch so we both see the results at the same time, Mike would be there also. I've no intention to BS my way around a problem, I'm far more interested in finding out exactly what has gone on.

It's possible the cam gears simply took one for the team & have virtually all the foreign material present in the entire system - seems bloody strange but I can't rule it out.

Are you prepared to work out a deal for replacing/ repairing what we had & see if we have success? I have piles of old gears I could send as cores, the time & materials cost to yourself would be small fraction of what this thing has cost myself.

I have no answer as to where the brass/bronze could have come from, the only metal similar in the engine is the little end bushes, these were in perfect condition at inspection, crank and rod bearings were brand new.

 

The stock sprockets need roughly 12 to 15 psi to fully activate.

In my opinion, a healthy engine with a stock oil pump will easily generate the oil pressure (25 psi) needed to fully activate my rebuilds.

 

I have no problem with supplying a fresh set. The one is scrap, but the other should be able to be honed and cleaned. I can supply a replacement core in advance and if all goes well, I'll leave it up to you and Mike to send a replacement.

I don't know whether a refund has been issued or not, I will contact Z1 to get an update.

 

Don't get me wrong I was never gunning for a refund, just a working product, if we determine it's a fault of the engine then so be it but it is essential for me to determine EXACTLY what is at fault. If we fit a new/repaired pair & there are no issues then I'll be happy to accept it must have been an issue with oil contamination & it must have effected the gears & nothing else.

It is plausible that due to the centrifugal nature of the spinning gears they retained the heavier particles in the oil - kind of like a secondary filter - but in one of the worst possible places to store the crap.

 

Just heard back from Brett

He is sending us some repaired/rebuilt gears suitable for fitting back in the engine to see how it goes

This is a good result as far as I am concerned & all credit to Brett for standing behind his product even when he may have some doubt over the actual cause of the issue.

I will be fitting the gears back to the engine free of charge & we will pull the filter & cut it open & change the oil - it's due for that in any case.

I will post pics of the filter element when we get it out, if there's contaminants that cause concern I guess I will be doing what we used to call a "bulk strip" - the engine is pulled down as far as is needed to establish what is going on, from there you make the call to fully strip or just repair whatever may be wrong.

Quite keen to get to the bottom of this and establish what has gone on (if we can) regardless of blame or fault as long as we know the cause then we can avoid it in the future.

 

If bronze valve guides .. check them !

I decided to go with OEM in my build .

 

Thread now cleaned of off topic posts.

Infractionate button ready to be pressed for any future transgressions of the guidelines.

 

Dave,

I just want to clarify that this is not a "noise" related issue. Rather, Glenn found one sprocket would not advance consistently when the VTC was activated and it would intermittently fail to return to the static, zero advance position when the VTC was off. As far as I know, the second sprocket worked without issue even though it had signs of debris being in it.

 

That's correct Brett
At the start we had a trouble at full temp with both but after diagnosing the cam bearings being out of spec the one gear worked perfectly.

If the other gear has had contaminants get in there while it was on the motor then it IS extremely likely this could cause it to have problems operating.

Car of doom due at the shop mid tomorrow morning for an oil & filter change, if there is any sign of debris over an above the expected normal amount (I challenge anyone to build a motor & not have any metal in the filter while breaking it in - there is ALWAYS a small amount of small particles) then action will be taken to find out what it is and where it came from. (as I have said already)

Brett has been extremely good about all this and has stood behind his product with pride. I have to say if any of these posts seem to come across the wrong way it's more because of the frustration from this car over the years than it is because of these gears.
I believe 100% that if I had fitted these to my own car or any other Zed in the shop at the time they would have worked with no issues at all.
This damn car however can and will grab every chance it can get to screw you over, ask anyone who really knows the car, it's evil pure evil LOL!

My comment re not fitting these without owner accepting full responsibility - well really at the end of the day that should apply to ANY after market components to be fair.
Most race type parts offer zero warranty, Brett however clearly stands behind his kudos to him.

 

BDE not returning to zero

Brett/mungy,

Sorry to hijack this thread, however, I have a set of BDE gears and I suspect that one or both of mine also aren't returning back to zero. No matter how rich I make the AFR at idle, sometimes it's OK, but most of the time I get missing that I've only been able to put down to the valve timing being still advanced. I almost always get noise from the BDE VTC gears too. Worst at cold start but present all the time to some extent. FYI, I have JWT R5 cams and JWT HD valve springs.

-ltd